Patent GB-190417492-A (GB)
Title: Improvements in Printing Machines
Inventor: WHITEMAN WILLIAM THOMAS
Filed: 1904-08-11
Granted: 1904-10-06
Abstract: 17,492. Whiteman, W. T., [White, J.]. Aug. 11. Lithographic and like printing. - Relates to lithographic and other printing-machines in which the design is impressed on the sheet of paper or other mat e r i a l through the agency of an intermediate transfer roller. The forme cylinder 2 and impression cylinder 4 are mounted in adjustable bearings 11, 25 in the frame 1 of the machine, and means are provided for automatically placing the transfer cylinder 3 alternately in contact with these cylinders, Figs. 1, 2. The cylinders 1, 2, 3 are provided with spur-wheels 18, 19, 20 respectively, which are constantly in gear with one another. The printing-surface 5, which in this case consists of a thin plate of aluminium secured by clamps 6, occupies about half the circumference of the cylinder 2, and is damped and inked twice by sets of rollers 8, 7 respectively before transferring the design to a flexible transfer surface 15 of cloth and india-rubber, stretched on the cylinder 3 by a clamp 16 and a roller 17. The remaining portion of the surface of the cylinder 2 is furnished with an ink-slab 9 which assists in distributing the ink, supplied from suitable reservoirs. The transfer cylinder 3 is mounted loosely on an eccentric shaft 28, the end 32 of which carries a worm-wheel 33, with which a constantly-rotatiug worm 34, on a shaft 35, mounted in bearings 43 on a three-armed lever 44, may be thrown in and out of gear. The same effect may also be produced by providing the shaft 28 with concentric ends and mounting them in eccentric bushes in the frame 1. The shaft 35 is driven by means of bevel gearing 36, 37, the wheel 37 being mounted on a shaft 38, carrying a pinion 39 which is constantly operated from the spur-wheel 18 by means of gearing 40, 42. The lever 44 is pivoted by its hub 45 on the shaft 38, and its third arm carries a roller 47, which rides upon the periphery of a concentric disc 46 fast on the end 32 of the shaft 38, thus keeping the worm 34 in gear with the worm-wheel 33 against the action of a spring 48. The disc 46 is provided with diametricallyopposite recesses 49, 50, into which the roller 47 drops as the disc revolves, thus throwing the worm and worm-wheel out of gear and securely holding the shaft 28 stationary during the operation of transferring the design from the printing- surface to the transfer cylinder, or from the transfer cylinder to the sheets. A separate locking-device may be provided if desired. Two other recesses 51, 52 are also provided which come into action when the transfer cylinder is thrown out of contact with both the cylinders 2, 4. A segmental guard-plate 53, of the same radius as the disc 46 and concentric with it, and furnished with an arm 54, fits loosely on the disc hub. This guard-plate is moved alongside the recesses in the disc 46, raising the roller 47 and again setting the shaft 28 in motion, by a bar 55 connected to the arm 54 and carrying a pin 56 which engages a suitablytimed cam 57 on the shaft 10 of the cylinder 2. To throw the cylinder 3 out of contact with both the cylinders 2, 4, a pin is secured in the recess 59 in the bar 55, in which position the guard-plate 53 uncovers one of the recesses 51, 52, permitting the roller 47 to drop into it and throw the worm 34 out of gear. This may be effected by a foot-operated or other device if desired. In the machine described, the diameters of the cylinders 3, 4 are equal, and equal to two-thirds of that of the forme cylinder 2. In a modification, the transfer cylinder may be placed alternately in printing relation with the forme and impression cylinders by mounting both the latter in eccentric bearings operated by suitable mechanism, the transfer roller remaining fixed. A modification is described, in which the diameters of the forme and impression cylinders are equal, and equal to two-thirds of that of the transfer cylinder, the printing-surface occupying about half of the circumference of the forme cylinder. By thus proportioning the cylinders, the forme passes under the damping and inking rollers three times before coming in contact with the transfer surface, and the forme and impression surfaces are brought successively into contact with the transfer surface without moving the transfer cylinder. A device for tripping the transfer cylinder is described. The sheets of tin, wood, glass, or other material to be printed are fed between the cylinders 3, 4 against a stop 27 on the cylinder 4, and, after being printed, are delivered over guides 63 pivoted on a spindle 63<1> on to a swinging frame 64, consisting of longitudinal laths 68 carried by a rocking shaft 70, Fig. 9. A radial arm 73 on the shaft 70 is connected by a rod 74 with a lever 75, which is operated by a cam 78 on a shaft 80. This shaft is driven by gear-wheels 81, 81<1> in the ratio of three to one, from the shaft carrying the cylinder 4. The frame 64 swings into a horizontal position, as shown, and deposits the sheets on to a carrier 65, which delivers them beneath the feedboard. The carrier 65 consists of a set of continuously-moving endless tapes 84, passing around pulleys 85, 87, and another set 91 passing around pulleys 87, 92. The tapes are driven from a pulley 94 on the shaft of the cylinder 4 by a crossed belt 90. If desired, the delivery frame 64 may be dispensed with, and the sheets allowed to fall directly on to the travelling tapes. In a modified form of delivery apparatus, the delivery frame consists of a number of transverse bars secured to a swinging bracket. The frame deposits the sheets on to a transverse carrier of continuously-moving tapes, which delivers them at the side of the machine.